A great truth is a truth whose opposite is also a great truth.
— Christopher Morley

Mathematics is the handwriting on the human consciousness of the very Spirit of Life itself.
— Claude Bragdon

We can hardly imagine a state of mind in which all material objects were regarded as symbols of spirtual truths or episodes in sacred history. Yet, unless we make this effort of imagination, Medieval art is largely incomprehensible.
— Kenneth Clark

The reasonable man adapts himself to the world; the unreasonable one persists in trying to adapt the world to himself. Therefore all progress depends on the unreasonable man.
— George Bernard Shaw

The animals went in two by two Hurrah, hurrah.
— Popular Song

God is odd. He love the odd.
— Muslim Saying

I love her whose number is 545.
— Graffiti from Pompei

(x + y)² = x² + 2xy + y²
therefore God exists.
— Leonhard Euler to Catherine the Great

Music is the pleasure the human soul experiences from counting
without being aware that it is counting.
— Gottfried Lebniz

Mathematicians are a species of Frenchmen: if you say something to them they translate it into their own language and presto! it is something entirely different.
— Goethe, Maxims and Reflexions, (1829)

I have come to believe that the whole world is an enigma, a harmless enigma that is made terrible by our won mad attempt to interpret it as though it had an underlying truth.
— Umberto Eco

There is a very good saying that if triangles invented a god,
they would make him three-sided.
— Baron De Montesquieu

Between the idea
And the reality
Between the motion
And the act
Falls the Shadow

— T.S. Eliot

What goes up a chimney down but won't go down a chimney up?
— Anonymous Riddle

My theology, briefly, is that the universe was dictated but not signed.
— Christopher Morley

Physics is an otherworld thing, it requires a taste for things unseen, even unheard of—
a high degree of abstraction... These faculties die off somehow when you grow up...
profound curiosity happens when children are young. I think physicists are the Peter Pans
of the human race... Once you are sophisticated, you know too much— far too much.
Pauli once said to me, “I know a great deal. I know too much. I am a quantum ancient.”.
— Isidor Rabi

Poets do not go mad; but chess playeres do. Mathematicians go mad, and cashiers;
but creative artists very seldom. I am not, as will be seen, in any sense attacking logic:
I only say that this danger does lie in logic, not in imagination.
— G.K. Chesterton

I remember once going to see him [Ramanujan] when he was lying ill at Putney. I had ridden in taxi-cab No. 1729, and remarked that the number seemed to me rather a dull one, and that I hoped it was not an unfavourable omen. "No," he replied, "it is a very interesting number; it is the smallest number expressible as a sum of two cubes in two different ways."
— G.H. Hardy

The point of philosophy is to start with something so simple as to seem not worth stating, and to end with something so paradoxical that no one will believe it.
— Bertrand Russell

Intuition is reason in a hurry.
— Holbrook Jackson

On the basis of my historical experience, I fully believe that mathematics of the 25th century will be as different from that of today as the latter is from that of the 16th century.
— George Sarton

A mathematician is a blind man in a dark room looking for a black cat which isn't there.
— Charles Darwin

I knew a mathematician who said, "I do not know as much as God,
but I know as much as God did at my age.
— Milton Shulman

The old men asks for more time, while the young waste it. And the philosopher smiles,
knowing there is none there. But the hero stands sword drawn at the looking glass
of his mind, aiming at that anonymous face over his shoulder.
— R. S. Thomas

My theory stands as firm as a rock; every arrow directed against it will return quickly
to its archer. How do I know this? Because I have studied it from all sides for many years;
because I have examined all objections which have ever been made against the infinite numbers; and above all because I have followed its roots, so to speak, to the first infallible cause of all created things.
— Georg Cantor, Contributions to the Founding of the Theory of Transfinite Numbers

Ask not what's inside your head but what your head's inside of.
— William Mace

Why, for example, should a group of simple, stable compounds of carbon, hydrogen, oxygen, and nitrogen struggle for billions of years to organize themselves into a professor of chemistry? What's the motive?
— Robert Pirsig

If the flesh came for the sake of spirit, it is a miracle.
But if the spirit for the sake of the flesh— it is a miracle of miracles.
— The Gospel of Thomas

I imagine that whenever the mind perceives a mathematical idea, it makes contact with Plato's world of mathematical concepts... When mathematicians communicate, this is made possible by each one having a direct route to truth, the consciousness of each being in a position to perceive mathematical truths directly, through the process of 'seeing'.
— Roger Penrose, The Emperor's New Mind (1989)

Note: All the quotes above were selected from John D. Barrow's
Pi in the Sky: Counting, Thinking, and Being (1992)